I think the evidence to date is pretty overwhelming (both scientifically and anecdotally) that low-carb diets are sound in preventing and treating weight gain and diabetes, as long as overall
quality of food and calories still being consumed are not ignored. And naturally, one still has to get plenty of exercise, rest, lower stress, etc.
In addition to dietary change, I believe some people need medication in order to correct the serotonin and/or dopamine issues that cause them to be overly drawn towards unhealthy carbs and sweets (or alcohol, for that matter) and overeating. This element of treatment is often ignored because our society is big on believing in doing things on sheer willpower, a limited viewpoint that holds many people back IMHO. Dealing with brain chemistry correctly could be key to long-term success with overeating or carb addiction.
I don't personally cut out fruits, vegetables, or a starch like sweet potatoes. I eat butter, full-fat dairy, EVOO, and extra-virgin coconut oil. (I have excellent cholesterol numbers, although that could just be good luck on my part.) I did cut out all soda, beer, wine, muffins, bagels, bread, and pasta. Not for diabetes (I actually have just the opposite problem, low blood sugar), but because my stomach was killing me and I knew they were piling on the pounds. It resolved ALL of my stomach pain and problems, eased PMS symptoms, relieved water retention issues, increased my energy, and I lost a lot of weight. I also cut out chocolate, discovering it is a trigger food for me that causes breakouts, increases sinus problems, and irritates my stomach. Soy is another problem for me, but that's another story! I have an extreme tendency towards obesity, and fibromyalgia makes me overly sensitive to many foods. People need not be as extreme as I was. But it does give results. And don't worry, I still eat plenty!
Whenever I deviate from the cutout diet, I pay for it in stomach pain, a headache, fatigue, etc. It's not worth it!